Columbia sociologists Peter Sheridan Dodds, Duncan Watts and their colleagues have published the first results of the Small World Project, which uses the Internet to test the six degrees of separation theory. In this previously recorded video, Watts explains the theory that originated in the 1960s and contends that people are connected through a chain of no more than six people.

They set up an experiment in which individuals would try to get a message to a stranger somewhere else in the world through the Internet. Participants knew basic facts about the 18 targets: name, location, profession and some educational background.

More than 61,000 individuals from 166 countries signed up for the experiment and created a total of 24,163 message chains. Only 384 of the chains, however, reached their targets.

Of the chains that were completed, it took an average of four message relays, but Watts said "that is a misleading number because it is biased toward short chains." Longer chains, he said, are more likely to end due to lack of participating.

To compensate for this bias, he said, the researchers estimated how many messages would have to be relayed if there was perfect cooperation.

"That estimate is five to seven, with an average of six," he said. "That is the true answer and that is what the world actually looks like from the point of view of how the network is connected."